Unidentifiable fossils: palaeontological problematica
There is a detailed vocabulary used to describe organisms which defy classification and a system of nomenclature to denote confidence limits on probable or speculative affinities, but they are generally grouped together as “problematica”. A handy grab-bag of misfits that have exasperated or eluded scientists, ready for future generations to have a go at. In museums, problematica specimens reside in drawers and cabinets equivalent to the ubiquitous drawer of odds and sods that most people have in the kitchen.
via https://www.theguardian.com/science/2018/jul/26/unidentified-fossils-palaeontological-problematica